A laser marker enables efficient determination of an optimum condition for a printing pattern of a two-dimensional code and simplification of the evaluation operation of the printing pattern of the two-dimensional code. A printing pattern regarding a cell to be printed in each of reference cells of a two-dimensional code is generated. The two-dimensional code is printed in this cell printing pattern. The recognition rate of the two-dimensional code is calculated on the basis of the reference cells. When the recognition rate is a predetermined value or more, a present printing pattern is stored as an optimum condition (optimum printing pattern) in a database. In contrast, when the recognition rate is less than the predetermined value, the size of cells constituting the present printing pattern is changed. The two-dimensional code is printed in the changed cell printing pattern, and the recognition rate of the two-dimensional code is calculated again.